U.S. Secretary of State Mike Pompeo blamed Iran on Thursday for attacking oil tankers off the coast of the United Arab Emirates earlier this month.

“These were efforts by the Iranians to raise the price of crude oil throughout the world,” he told reporters before departing for Europe, where he met for 45 minutes with German Chancellor Angela Merkel in Berlin on Friday to discuss Iran and other issues.

Earlier in the day, U.S. National Security Advisor John Bolton stated that Iran was behind the attack.

“Oh, yes. Ambassador Bolton got it right,” when seeing the evidence, said Pompeo.

This development comes as tension between Iran and the United States, and its Gulf partners, has increased in the past month.

The United States enacted new sanctions and deployed two warships with fighter jets, in addition to a Patriot missile battery, to the Gulf in response to Pentagon reports that Iran’s Islamic Revolutionary Guard Corps was planning an attack on U.S. forces or interests in the region.